Abstract: A remotely controllable circuit breaker and switch for controlling the flow of current from a three phase AC power source to a three phase load, and usable in either wye or delta configurations. A latching relay controls the current for each phase. Current samples in the three phases are scaled and converted to DC values by scalers and RMS to DC converters. The DC values are converted to digital current values by an analog-to-digital converter which sequentially scans the DC values of the currents in the three phases. A central processing unit monitors the digital current values to detect significant phase imbalances and overcurrents which persist for time periods which exceed allowable limits according to a predetermined time-dependent function, and to initiate opening of the relays in response thereto. The central processing unit also opens and/or resets the relays in response to remote control signals.

Abstract: A process control system for controlling a set of outputs according to a multiplicity of inputs. The process control system analyzes the condition of the inputs as though they were arranged in a hypothetical ladder diagram which is a representation of the circuitry that would be required to control the loads if simple switches were interconnected, by wires, in the conventional way to control the loads. The hypothetical ladder diagram includes a plurality of hypothetical horizontal rows of circuit elements in which the circuit elements are also located in hypothetical vertical columns. All of the hypothetical vertical columns, except the last, are "input" vertical columns since they represent input circuit elements. The last vertical column contains the loads (or outputs) and is an "output" vertical column.